Create ata.h

implement the base ata pio mode driver so that the filesystems like fat16, fat32 work. This is the header for that. It will need a iso9660 driver for cdrom etc optical media

Makefile

@@ -8,13 +8,8 @@ OBJCOPY = i386-elf-objcopy
 BUILD_DIR = build
 CROSS_DIR = cross
 DISK_IMG = $(BUILD_DIR)/disk.img
-
-STAGE2_ADDR = 0x7e00
 STAGE2_SIZE = 2048
 
-# Place the memory map (e820) past stage2 bl in memory
-MEMMAP_BASE = $(shell echo $$(($(STAGE2_ADDR) + $(STAGE2_SIZE))))
-
 KERNEL_C_SRC = $(wildcard kernel/*.c)
 KERNEL_ASM_SRC = $(wildcard kernel/*.asm)
 KERNEL_OBJ = $(patsubst kernel/%.c, $(BUILD_DIR)/%.o, $(KERNEL_C_SRC))
@@ -34,7 +29,7 @@ stage1: $(BUILD_DIR)
 # NOTE: Stage2 final size should be checked against `$(STAGE2_SIZE)` by the build system to avoid an overflow.
 # Alternatively, convey the final stage2 size through other means to stage1.
 stage2: $(BUILD_DIR)
-	$(AS) $(ASFLAGS) -DMEMMAP_BASE=$(MEMMAP_BASE) -o $(BUILD_DIR)/stage2.o bootloader/stage2.asm
+	$(AS) $(ASFLAGS) -o $(BUILD_DIR)/stage2.o bootloader/stage2.asm
 	$(CC) -std=c11 -ffreestanding -nostdlib -nostdinc -fno-stack-protector -m32 -Iklibc/include -g -c -o $(BUILD_DIR)/stage2_load.o bootloader/stage2_load.c
 	$(LD) -Tbootloader/stage2.ld -melf_i386 -o $(BUILD_DIR)/$@.elf $(BUILD_DIR)/stage2.o $(BUILD_DIR)/stage2_load.o
 	$(OBJCOPY) -O binary $(BUILD_DIR)/$@.elf $(BUILD_DIR)/$@.bin
@@ -44,7 +39,7 @@ $(BUILD_DIR)/asm_%.o: kernel/%.asm
 	$(AS) $(ASFLAGS) -o $@ $<
 
 $(BUILD_DIR)/%.o: kernel/%.c
-	$(CC) -DMEMMAP_BASE=$(MEMMAP_BASE) -std=c11 -ffreestanding -nostdlib -nostdinc -fno-stack-protector -m32 -Iklibc/include -g -c -o $@ $<
+	$(CC) -std=c11 -ffreestanding -nostdlib -nostdinc -fno-stack-protector -m32 -Iklibc/include -g -c -o $@ $<
 
 $(BUILD_DIR)/klibc/%.o: klibc/src/%.c
 	$(CC) -std=c11 -ffreestanding -nostdlib -nostdinc -fno-stack-protector -m32 -Iklibc/include -g -c -o $@ $<

bootloader/README.md

@@ -11,16 +11,16 @@ Bootloader documentation for ClassicOS
 
 ## Stage 1 (`stage1.asm`)
 
+Responsible for loading the second stage using BIOS routines, and switching to protected mode.
+
 - Queries CHS parameters from BIOS
 - Loads the second stage bootloader (2048 B) to `0x7c00`
+- Sets up a GDT with descriptor entries for code and data both covering the whole 32-bit address space
 - Enables A20
-- Jumps to stage2
+- Set CR0.PE (enable protected mode) and jump to stage 2
 
 ## Stage 2 (`stage2.asm, stage2_load.c`)
 
-- Read and store E820 memory map from BIOS
-- Sets up a GDT with descriptor entries for code and data both covering the whole 32-bit address space
-- Set CR0.PE (enable protected mode)
 - Set up segment registers
 - Load the kernel ELF header
 - Parse the program headers, and load all `PT_LOAD` segments from disk

bootloader/stage1.asm

@@ -40,8 +40,11 @@ _start:
     call enable_a20
     jc a20_error                ; Jump if A20 enable fails
 
-    ; Jump to s2
+    ; Setup Global Descriptor Table
-    jmp 0x7e00
+    call setup_gdt
+
+    ; Switch to protected mode and jump to second stage at 0x08:0x7E00
+    call switch_to_pm
 
 disk_error:
     mov si, disk_error_msg
@@ -238,6 +241,30 @@ check_a20:
     clc                      ; Clear carry flag to indicate success
     ret
 
+; ----------------------------------------------------------------
+gdt_start:
+    dq 0x0000000000000000         ; Null descriptor
+    dq 0x00CF9A000000FFFF         ; 32-bit code segment (selector 0x08)
+    dq 0x00CF92000000FFFF         ; 32-bit data segment (selector 0x10)
+    dq 0x00009A000000FFFF         ; 16-bit code segment for real mode (selector 0x18)
+
+gdt_descriptor:
+    dw gdt_end - gdt_start - 1
+    dd gdt_start
+gdt_end:
+
+setup_gdt:
+    lgdt [gdt_descriptor]
+    ret
+
+; ----------------------------------------------------------------
+switch_to_pm:
+    cli
+    mov eax, cr0
+    or eax, 1
+    mov cr0, eax
+    jmp 0x08:0x7E00             ; jump to S2
+
 ; ----------------------------------------------------------------
 print_string_16:
 .loop:

bootloader/stage2.asm

@@ -1,80 +1,10 @@
+[BITS 32]
 global _start
+global ata_lba_read
+
 extern load_kernel
 
-%define e820_magic 0x534d4150 ; "SMAP"
-%define e820_entry_size 24
-%define e820_max_entries 128
-
-; ----------------------------------------------------------------
-; Real mode
-; ----------------------------------------------------------------
-[BITS 16]
 _start:
-    call read_e820
-    call setup_gdt
-    call switch_to_pm
-
-read_e820:
-    xor ebx, ebx
-    mov es, bx
-    mov di, MEMMAP_BASE+4       ; ES=0 DI=MEMMAP_BASE+4
-    xor bp, bp                  ; Keeping count in bp
-
-.e820_loop:
-    mov eax, 0xe820
-    mov ecx, e820_entry_size
-    mov edx, e820_magic
-    int 0x15
-    jc .done                    ; Error?
-
-    cmp eax, e820_magic         ; Verify "SMAP"
-    jne .done
-
-    test ecx, ecx               ; Skip 0-sized entries
-    jz .skip
-
-    add di, e820_entry_size     ; Advance write addr
-    inc bp                      ; Increment count
-
-    cmp bp, e820_max_entries    ; Stop if we're at capacity
-    jae .done
-.skip:
-    test ebx, ebx
-    jne .e820_loop
-.done:
-    mov [MEMMAP_BASE], bp       ; Store count
-    ret
-
-setup_gdt:
-    lgdt [gdt_descriptor]
-    ret
-
-switch_to_pm:
-    cli
-    mov eax, cr0
-    or eax, 1
-    mov cr0, eax
-    jmp 0x08:pm_entry
-
-e820_count:
-    dw 0
-
-gdt_start:
-    dq 0x0000000000000000         ; Null descriptor
-    dq 0x00CF9A000000FFFF         ; 32-bit code segment (selector 0x08)
-    dq 0x00CF92000000FFFF         ; 32-bit data segment (selector 0x10)
-    dq 0x00009A000000FFFF         ; 16-bit code segment for real mode (selector 0x18)
-gdt_descriptor:
-    dw gdt_end - gdt_start - 1
-    dd gdt_start
-gdt_end:
-
-; ----------------------------------------------------------------
-; Protected mode
-; ----------------------------------------------------------------
-[BITS 32]
-
-pm_entry:
     ; Set up segments
     ; Data segments
     mov ax, 0x10
@@ -88,8 +18,9 @@ pm_entry:
     mov ax, 0x08
     mov cs, ax
 
-    ; Stack
+    ; Stack (must be identity-mapped)
     mov esp, 0x90000
 
     call load_kernel
+
     jmp eax

kernel/ata.c

@@ -1,119 +0,0 @@
-#include "ata.h"
-#include "io.h"
-#include "print.h"
-
-#define ATA_TIMEOUT 100000
-
-static inline void ata_delay(void) {
-    /* 400ns delay by reading alternate status */
-    inb(ATA_PRIMARY_CTRL);
-    inb(ATA_PRIMARY_CTRL);
-    inb(ATA_PRIMARY_CTRL);
-    inb(ATA_PRIMARY_CTRL);
-}
-
-bool ata_wait_ready(void) {
-    for (int i = 0; i < ATA_TIMEOUT; i++) {
-        uint8_t status = inb(ATA_PRIMARY_IO + ATA_REG_STATUS);
-        /* Must NOT be busy AND must be ready */
-        if (!(status & ATA_SR_BSY) && (status & ATA_SR_DRDY))
-            return true;
-    }
-    return false;
-}
-
-static bool ata_wait(uint8_t mask) {
-    for (int i = 0; i < ATA_TIMEOUT; i++) {
-        uint8_t status = inb(ATA_PRIMARY_IO + ATA_REG_STATUS);
-        /* If ERR is set, stop waiting and return failure */
-        if (status & ATA_SR_ERR) return false;
-        
-        if (!(status & ATA_SR_BSY) && (status & mask))
-            return true;
-    }
-    return false;
-}
-
-bool ata_init(void) {
-    /* Select drive */
-    outb(ATA_PRIMARY_IO + ATA_REG_HDDEVSEL, ATA_MASTER);
-    ata_delay();
-
-    /* Check if drive exists */
-    uint8_t status = inb(ATA_PRIMARY_IO + ATA_REG_STATUS);
-    if (status == 0xFF || status == 0) return false;
-
-    outb(ATA_PRIMARY_IO + ATA_REG_COMMAND, ATA_CMD_IDENTIFY);
-    ata_delay();
-
-    if (!ata_wait(ATA_SR_DRQ))
-        return false;
-
-    uint16_t identify[256];
-    for (int i = 0; i < 256; i++)
-        identify[i] = inw(ATA_PRIMARY_IO);
-
-    print_string("[ATA] Primary master detected\n");
-    return true;
-}
-
-bool ata_read_sector(uint32_t lba, uint8_t* buffer) {
-    if (!buffer) return false;
-
-    /* 1. Wait for drive to be ready for command */
-    if (!ata_wait_ready()) return false;
-
-    /* 2. Setup Task File (LBA28) */
-    outb(ATA_PRIMARY_IO + ATA_REG_HDDEVSEL, 0xE0 | ((lba >> 24) & 0x0F));
-    outb(ATA_PRIMARY_IO + ATA_REG_SECCOUNT0, 1);
-    outb(ATA_PRIMARY_IO + ATA_REG_LBA0, (uint8_t)(lba));
-    outb(ATA_PRIMARY_IO + ATA_REG_LBA1, (uint8_t)(lba >> 8));
-    outb(ATA_PRIMARY_IO + ATA_REG_LBA2, (uint8_t)(lba >> 16));
-    
-    /* 3. Issue Read Command */
-    outb(ATA_PRIMARY_IO + ATA_REG_COMMAND, ATA_CMD_READ_PIO);
-
-    /* 4. Wait for Data Request (DRQ) */
-    if (!ata_wait(ATA_SR_DRQ))
-        return false;
-
-    /* 5. Transfer data */
-    for (int i = 0; i < 256; i++) {
-        uint16_t data = inw(ATA_PRIMARY_IO);
-        buffer[i * 2]     = data & 0xFF;
-        buffer[i * 2 + 1] = (data >> 8) & 0xFF;
-    }
-
-    ata_delay();
-    return true;
-}
-
-bool ata_write_sector(uint32_t lba, const uint8_t* buffer) {
-    if (!buffer) return false;
-
-    /* 1. Wait for drive to be ready for command */
-    if (!ata_wait_ready()) return false;
-
-    /* 2. Setup Task File */
-    outb(ATA_PRIMARY_IO + ATA_REG_HDDEVSEL, 0xE0 | ((lba >> 24) & 0x0F));
-    outb(ATA_PRIMARY_IO + ATA_REG_SECCOUNT0, 1);
-    outb(ATA_PRIMARY_IO + ATA_REG_LBA0, (uint8_t)(lba));
-    outb(ATA_PRIMARY_IO + ATA_REG_LBA1, (uint8_t)(lba >> 8));
-    outb(ATA_PRIMARY_IO + ATA_REG_LBA2, (uint8_t)(lba >> 16));
-    
-    /* 3. Issue Write Command */
-    outb(ATA_PRIMARY_IO + ATA_REG_COMMAND, ATA_CMD_WRITE_PIO);
-
-    /* 4. Wait for drive to request data */
-    if (!ata_wait(ATA_SR_DRQ))
-        return false;
-
-    /* 5. Transfer data */
-    for (int i = 0; i < 256; i++) {
-        uint16_t word = buffer[i * 2] | (buffer[i * 2 + 1] << 8);
-        outw(ATA_PRIMARY_IO, word);
-    }
-
-    ata_delay();
-    return true;
-}

kernel/ata.h

@@ -32,13 +32,12 @@
 #define ATA_SR_ERR         0x01
 
 /* Drive select */
-#define ATA_MASTER         0xA0
+#define ATA_MASTER         0x00
-#define ATA_SLAVE          0xB0
+#define ATA_SLAVE          0x10
 
 /* Public API */
 bool ata_init(void);
 bool ata_read_sector(uint32_t lba, uint8_t* buffer);
 bool ata_write_sector(uint32_t lba, const uint8_t* buffer);
-bool ata_wait_ready(void);
 
 #endif

kernel/display.c

@@ -1,80 +1,36 @@
-#include <string.h>
 #include "display.h"
-#include "io.h"
+#include "io.h" // Include your I/O header for port access
 #include "vga.h"
 
 // Initialize the display
 void init_display(void) {
-    // Initialize the VGA driver. This typically sets up the 80x25 text mode,
+    // Initialize VGA settings, if necessary
-    // clears the screen, and sets the cursor.
+    // This could involve setting up the VGA mode, etc.
-    vga_init();
+    set_display_mode(0x13); // Example: Set to 320x200 256-color mode
 }
 
 // Enumerate connected displays
 void enumerate_displays(void) {
-    // This function is often a complex operation in a real driver.
+    // This is a simplified example. Actual enumeration may require
-    // In this simplified kernel/VGA text mode environment, we use printf
+    // reading from specific VGA registers or using BIOS interrupts.
-    // to output a message and rely on the fact that VGA is present.
     
-    // Clear the display before printing a message
+    // For demonstration, we will just print a message
-    vga_clear(vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK));
+    // In a real driver, you would check the VGA registers
-    
+    // to determine connected displays.
-    // Output a simplified enumeration message
+    clear_display();
-    vga_printf("Display: Standard VGA Text Mode (80x25) Detected.\n");
+    // Here you would typically read from VGA registers to find connected displays
-    
+    // For example, using inb() to read from VGA ports
-    // In a real driver, you would use inb() and outb() with specific VGA ports
-    // to read information (e.g., from the CRTC registers 0x3D4/0x3D5)
-    // to check for display presence or configuration.
 }
 
 // Set the display mode
-// NOTE: Setting arbitrary VGA modes (like 0x13 for 320x200) is very complex
-// and requires writing hundreds of register values, often done via BIOS in
-// real mode. Since we are in protected mode and have a simple text driver,
-// this function is kept simple or treated as a placeholder for full mode changes.
 void set_display_mode(uint8_t mode) {
-    // Check if the requested mode is a known mode (e.g., VGA Text Mode 3)
+    // Set the VGA mode by writing to the appropriate registers
-    // For this example, we simply acknowledge the call.
+    outb(VGA_PORT, mode); // Example function to write to a port
-    // A true mode set would involve complex register sequencing.
-    
-    // The provided vga.c is a Text Mode driver, so a graphical mode set
-    // like 0x13 (320x200 256-color) would break the existing vga_printf functionality.
-    
-    // A simplified text-mode-specific response:
-    if (mode == 0x03) { // Mode 3 is standard 80x25 text mode
-        vga_printf("Display mode set to 80x25 Text Mode (Mode 0x03).\n");
-        vga_init(); // Re-initialize the text mode
-    } else {
-        // Simple I/O example based on the original structure (Caution: Incomplete for full mode set)
-        outb(VGA_PORT, mode); // Example function to write to a port
-        vga_printf("Attempting to set display mode to 0x%x. (Warning: May break current display)\n", mode);
-    }
 }
 
 // Clear the display
 void clear_display(void) {
-    // Use the VGA driver's clear function, typically clearing to black on light grey
+    // Clear the display by filling it with a color
-    // or black on black. We'll use the black on light grey from vga_init for consistency.
+    // This is a placeholder for actual clearing logic
-    vga_clear(vga_entry_color(VGA_COLOR_BLACK, VGA_COLOR_LIGHT_GREY));
+    // You would typically write to video memory here
-    // Reset cursor to 0, 0
-    vga_set_cursor_position(0, 0);
-}
-
-// Helper function to write a string
-void display_write_string(const char* str) {
-    // Use the VGA driver's string writing function
-    vga_write_string(str, strlen(str));
-}
-
-// Helper function to print a formatted string
-void display_printf(const char* format, ...) {
-    // Use the VGA driver's printf function
-    va_list args;
-    va_start(args, format);
-    
-    // The vga_printf function already handles the va_list internally,
-    // so we can just call it directly.
-    vga_printf(format, args);
-    
-    va_end(args);
 }

kernel/display.h

@@ -2,21 +2,13 @@
 #define DISPLAY_H
 
 #include <stdint.h>
-#include "vga.h" // Include VGA functions
 
-#define VGA_PORT 0x3C0  // Base port for VGA (Often used for general control, though 0x3D4/0x3D5 are used for cursor)
+#define VGA_PORT 0x3C0  // Base port for VGA
 
 // Function prototypes
 void init_display(void);
 void enumerate_displays(void);
-void set_display_mode(uint8_t mode); // In this context, modes are typically BIOS or VESA modes, which are complex.
+void set_display_mode(uint8_t mode);
-                                      // We'll treat this as a placeholder/simple mode call.
 void clear_display(void);
 
-// New function to write a string using the VGA driver
-void display_write_string(const char* str);
-
-// New function to print a formatted string using the VGA driver
-void display_printf(const char* format, ...);
-
 #endif // DISPLAY_H

kernel/gui.c

@@ -1,66 +0,0 @@
-#include "gui.h"
-#include "vga.h"  // VGA functions for drawing and clearing screen
-#include "framebuffer.h"  // For pixel manipulation if needed
-
-// Initialize the GUI (could set up any global state or variables here)
-void gui_init(void) {
-    // Clear the screen with black or any color
-    gui_clear(vga_entry_color(VGA_COLOR_BLACK, VGA_COLOR_WHITE));
-}
-
-// Draw a window (simple rectangle with a title)
-void gui_draw_window(gui_window_t* window) {
-    // Draw the window's border
-    for (uint32_t y = 0; y < window->height; ++y) {
-        for (uint32_t x = 0; x < window->width; ++x) {
-            // Check if we are at the border
-            if (x == 0 || y == 0 || x == window->width - 1 || y == window->height - 1) {
-                vga_put_entry_at('#', vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK), window->x + x, window->y + y);
-            } else {
-                // Fill the inside of the window
-                vga_put_entry_at(' ', vga_entry_color(VGA_COLOR_BLACK, VGA_COLOR_BLACK), window->x + x, window->y + y);
-            }
-        }
-    }
-
-    // Draw the title at the top
-    if (window->title) {
-        size_t i = 0;
-        while (window->title[i] != '\0' && i < window->width - 2) {
-            vga_put_entry_at(window->title[i], vga_entry_color(VGA_COLOR_WHITE, VGA_COLOR_BLACK), window->x + i + 1, window->y);
-            i++;
-        }
-    }
-}
-
-// Draw a button (a simple rectangle with text in the middle)
-void gui_draw_button(gui_button_t* button) {
-    for (uint32_t y = 0; y < button->height; ++y) {
-        for (uint32_t x = 0; x < button->width; ++x) {
-            // Check if we are at the border
-            if (x == 0 || y == 0 || x == button->width - 1 || y == button->height - 1) {
-                vga_put_entry_at('#', vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK), button->x + x, button->y + y);
-            } else {
-                // Fill the inside of the button
-                vga_put_entry_at(' ', vga_entry_color(VGA_COLOR_BLACK, VGA_COLOR_BLACK), button->x + x, button->y + y);
-            }
-        }
-    }
-
-    // Draw the label in the center of the button
-    size_t label_len = 0;
-    while (button->label[label_len] != '\0') {
-        label_len++;
-    }
-
-    size_t start_x = button->x + (button->width - label_len) / 2;
-    size_t start_y = button->y + (button->height - 1) / 2;
-    for (size_t i = 0; i < label_len; ++i) {
-        vga_put_entry_at(button->label[i], vga_entry_color(VGA_COLOR_WHITE, VGA_COLOR_BLACK), start_x + i, start_y);
-    }
-}
-
-// Clear the screen with a color
-void gui_clear(uint32_t color) {
-    vga_clear(color);  // Just clear the VGA screen with a solid color
-}

kernel/gui.h

@@ -1,34 +0,0 @@
-#ifndef GUI_H
-#define GUI_H
-
-#include <stdint.h>
-#include <stddef.h>
-
-#define GUI_WINDOW_WIDTH   80
-#define GUI_WINDOW_HEIGHT  25
-#define GUI_BUTTON_WIDTH   10
-#define GUI_BUTTON_HEIGHT  3
-
-// Window structure
-typedef struct {
-    uint32_t x, y;
-    uint32_t width, height;
-    uint32_t color;  // Background color
-    const char* title;
-} gui_window_t;
-
-// Button structure
-typedef struct {
-    uint32_t x, y;
-    uint32_t width, height;
-    uint32_t color;  // Background color
-    const char* label;
-} gui_button_t;
-
-// Function prototypes for GUI elements
-void gui_init(void);
-void gui_draw_window(gui_window_t* window);
-void gui_draw_button(gui_button_t* button);
-void gui_clear(uint32_t color);
-
-#endif // GUI_H

kernel/hid.c

@@ -1,65 +0,0 @@
-#include "hid.h"
-#include "usb.h"
-#include "mouse.h"
-#include "keyboard.h"
-#include "print.h"
-#include <stdint.h>
-#include <stdbool.h>
-
-// Global variables
-static bool hid_initialized = false;
-
-void hid_init(void) {
-    if (hid_initialized) return;
-    hid_initialized = true;
-
-    // Initialize keyboard and mouse HID handling
-    keyboard_init();
-    // Assume USB mouse has been initialized and is connected.
-    usb_hid_init(); // Initializes USB HID for both keyboard and mouse
-}
-
-void hid_process_report(uint8_t* report, uint8_t length) {
-    // Process the HID report based on its type
-    if (length == 8) {  // Assuming a standard 8-byte report for HID keyboard
-        keyboard_hid_report_t* k_report = (keyboard_hid_report_t*) report;
-        hid_process_keyboard_report(k_report);
-    } else if (length == 3) {  // Assuming a standard 3-byte report for HID mouse
-        mouse_hid_report_t* m_report = (mouse_hid_report_t*) report;
-        hid_process_mouse_report(m_report);
-    }
-}
-
-// Handle HID keyboard report
-void hid_process_keyboard_report(const keyboard_hid_report_t* report) {
-    // Iterate over the keycodes and process key presses
-    for (int i = 0; i < 6; i++) {
-        uint8_t keycode = report->keycodes[i];
-        if (keycode != 0) {
-            char key = scancode_map[keycode];
-            if (key) {
-                keyboard_buffer_add(key);
-            }
-        }
-    }
-}
-
-// Handle HID mouse report
-void hid_process_mouse_report(const mouse_hid_report_t* report) {
-    // Process mouse movement and button clicks
-    mouse_data.x += report->x;
-    mouse_data.y += report->y;
-    mouse_data.left_button = (report->buttons & 0x01) != 0;
-    mouse_data.right_button = (report->buttons & 0x02) != 0;
-
-    print_hex((uint32_t)mouse_data.x, 1, 1);
-    print_hex((uint32_t)mouse_data.y, 1, 1);
-    print_hex((uint32_t)report->buttons, 1, 1);
-}
-
-// Parse the HID descriptor (for parsing USB HID device descriptors)
-bool hid_parse_descriptor(uint8_t* descriptor, uint32_t length) {
-    // HID descriptors are defined in the USB HID specification, we'll need to parse them here.
-    // For now, just return true assuming we have a valid descriptor.
-    return true;
-}

kernel/hid.h

@@ -1,46 +0,0 @@
-#ifndef HID_H
-#define HID_H
-
-#include <stdint.h>
-#include <stdbool.h>
-
-// HID Report types
-#define HID_REPORT_INPUT  0x01
-#define HID_REPORT_OUTPUT 0x02
-#define HID_REPORT_FEATURE 0x03
-
-// HID usage page constants (USB HID)
-#define HID_USAGE_PAGE_GENERIC 0x01
-#define HID_USAGE_KEYBOARD 0x06
-#define HID_USAGE_MOUSE 0x02
-
-// HID keyboard and mouse data
-typedef struct {
-    uint8_t modifier;    // Modifier keys (shift, ctrl, alt, etc.)
-    uint8_t reserved;    // Reserved byte
-    uint8_t keycodes[6]; // Keycodes for keys pressed
-} keyboard_hid_report_t;
-
-typedef struct {
-    uint8_t buttons;     // Mouse buttons (bitwise: 0x01 = left, 0x02 = right, 0x04 = middle)
-    int8_t x;            // X axis movement
-    int8_t y;            // Y axis movement
-    int8_t wheel;        // Mouse wheel
-} mouse_hid_report_t;
-
-// Initialize the HID subsystem
-void hid_init(void);
-
-// Process an incoming HID report
-void hid_process_report(uint8_t* report, uint8_t length);
-
-// Process HID keyboard report
-void hid_process_keyboard_report(const keyboard_hid_report_t* report);
-
-// Process HID mouse report
-void hid_process_mouse_report(const mouse_hid_report_t* report);
-
-// USB HID report descriptor parsing
-bool hid_parse_descriptor(uint8_t* descriptor, uint32_t length);
-
-#endif // HID_H

kernel/keyboard.c

@@ -2,91 +2,64 @@
 #include "io.h"
 #include "isr.h"
 #include "terminal.h"
-#include <stddef.h>
 
 #define KEYBOARD_DATA_PORT 0x60
 #define KEY_BUFFER_SIZE 256
 
-// Use volatile so the compiler knows these change inside interrupts
+static char key_buffer[KEY_BUFFER_SIZE];
-static volatile char key_buffer[KEY_BUFFER_SIZE];
+static uint8_t buffer_head = 0;  // Write position (interrupt)
-static volatile uint8_t buffer_head = 0;
+static uint8_t buffer_tail = 0;  // Read position (get_char)
-static volatile uint8_t buffer_tail = 0;
+static uint8_t buffer_count = 0;
-static volatile uint8_t buffer_count = 0;
+static uint8_t buffer_index = 0;
 
-// Exported map: Removed 'static' so hid.c can reference it if needed
+// Basic US QWERTY keymap (scancode to ASCII)
-const char scancode_map[128] = {
+static const char scancode_map[128] = {
-    0,  27, '1', '2', '3', '4', '5', '6', '7', '8',
+    0,  27, '1', '2', '3', '4', '5', '6', '7', '8', // 0x00 - 0x09
-    '9', '0', '-', '=', '\b', '\t', 'q', 'w', 'e', 'r',
+   '9', '0', '-', '=', '\b', '\t', 'q', 'w', 'e', 'r', // 0x0A - 0x13
-    't', 'y', 'u', 'i', 'o', 'p', '[', ']', '\n', 0,
+   't', 'y', 'z', 'u', 'i', 'o', 'p', '[', ']', '\n', // 0x14 - 0x1D
-    'a', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', ';',
+    0, 'a', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', // 0x1E - 0x27
-    '\'', '`', 0, '\\', 'z', 'x', 'c', 'v', 'b', 'n',
+   ';', '\'', '`', 0, '\\', 'x', 'c', 'v', 'b', // 0x28 - 0x31
-    'm', ',', '.', '/', 0, '*', 0, ' ', 0
+   'n', 'm', ',', '.', '/', 0, '*', 0, ' ', 0,      // 0x32 - 0x3B
+    // rest can be filled as needed
 };
 
-/**
+// Interrupt handler for IRQ1
- * Shared function used by both PS/2 (callback) and USB (hid.c)
+void keyboard_callback(void) {
- * This fixes the "undefined reference to keyboard_buffer_add" error.
+    uint8_t scancode = inb(KEYBOARD_DATA_PORT);
- */
+
-void keyboard_buffer_add(char c) {
+    if (scancode & 0x80) return;  // Ignore key release
+
+    char c = scancode_map[scancode];
     if (!c) return;
 
     uint8_t next_head = (buffer_head + 1) % KEY_BUFFER_SIZE;
 
-    // If buffer is full, we must drop the key
+    // Drop key if buffer full
-    if (next_head == buffer_tail) {
+    if (next_head == buffer_tail) return;
-        return; 
-    }
 
     key_buffer[buffer_head] = c;
     buffer_head = next_head;
     buffer_count++;
 
-    // Echo to terminal
     terminal_putchar(c);
 }
 
-/**
+void keyboard_init() {
- * Hardware Interrupt Handler for PS/2
+    register_interrupt_handler(33, keyboard_callback); // IRQ1 = int 33 (0x21)
- */
-void keyboard_callback(void) {
-    uint8_t scancode = inb(KEYBOARD_DATA_PORT);
-
-    // Ignore break codes (key release)
-    if (scancode & 0x80) return; 
-
-    char c = scancode_map[scancode];
-    keyboard_buffer_add(c);
 }
 
-void keyboard_init(void) {
+// Blocking read (returns one char)
-    buffer_head = 0;
-    buffer_tail = 0;
-    buffer_count = 0;
-    // IRQ1 is usually mapped to IDT entry 33
-    register_interrupt_handler(33, keyboard_callback); 
-}
-
-/**
- * Blocking read with a safe HLT to prevent CPU 100% usage
- */
 char keyboard_get_char(void) {
-    char c;
+    while (buffer_count == 0) {
-
+        __asm__ __volatile__("hlt");  // Better than busy loop
-    while (1) {
-        __asm__ __volatile__("cli"); // Disable interrupts to check buffer_count safely
-        
-        if (buffer_count > 0) {
-            c = key_buffer[buffer_tail];
-            buffer_tail = (buffer_tail + 1) % KEY_BUFFER_SIZE;
-            buffer_count--;
-            __asm__ __volatile__("sti"); // Re-enable interrupts after reading
-            return c;
-        }
-
-        /* * IMPORTANT: 'sti' followed by 'hlt' is guaranteed by x86 
-         * to execute 'hlt' BEFORE the next interrupt can trigger.
-         * This prevents the race condition hang.
-         */
-        __asm__ __volatile__("sti; hlt"); 
     }
+
+    char c;
+    __asm__ __volatile__("cli");
+    c = key_buffer[buffer_tail];
+    buffer_tail = (buffer_tail + 1) % KEY_BUFFER_SIZE;
+    buffer_count--;
+    __asm__ __volatile__("sti");
+
+    return c;
 }

kernel/keyboard.h

@@ -1,12 +1,7 @@
 #ifndef KEYBOARD_H
 #define KEYBOARD_H
 
-#include <stdint.h>
-
 void keyboard_init(void);
-void keyboard_buffer_add(char c);
+char keyboard_get_char(void);  // Blocking read from buffer
-char keyboard_get_char(void);  
-
-extern const char scancode_map[128]; 
 
 #endif

kernel/memmap.c

@@ -1,18 +1,21 @@
 #include "memmap.h"
 
-#define BOOTLOADER_MEMMAP_COUNT_ADDR    MEMMAP_BASE
-#define BOOTLOADER_MEMMAP_ADDR          (MEMMAP_BASE + 4)
-
 uint32_t get_memory_map(memory_map_entry_t *map, uint32_t max_entries) {
-    // Read the number of entries found by the bootloader
-    uint32_t entries_found = *(uint32_t*)BOOTLOADER_MEMMAP_COUNT_ADDR;
-    memory_map_entry_t *bios_data = (memory_map_entry_t*)BOOTLOADER_MEMMAP_ADDR;
-
     uint32_t count = 0;
-    while (count < entries_found && count < max_entries) {
+
-        map[count] = bios_data[count];
+    if (max_entries >= 1) {
+        map[count].base_addr = 0x00000000;
+        map[count].length = 0x0009FC00;
+        map[count].type = 1;
+        count++;
+    }
+
+    if (max_entries >= 2) {
+        map[count].base_addr = 0x00100000;
+        map[count].length = 0x1FF00000;
+        map[count].type = 1;
         count++;
     }
 
     return count;
-}
+}

kernel/memmap.h

@@ -7,7 +7,6 @@ typedef struct {
     uint64_t base_addr;
     uint64_t length;
     uint32_t type;
-    uint32_t ext;
 } __attribute__((packed)) memory_map_entry_t;
 
 uint32_t get_memory_map(memory_map_entry_t *map, uint32_t max_entries);

kernel/mouse.c

@@ -5,7 +5,7 @@
 #include <stdbool.h>
 
 // Mouse buffer
-mouse_data_t mouse_data;
+static mouse_data_t mouse_data;
 
 // Read USB mouse data
 mouse_data_t usb_read_mouse(void) {

kernel/mouse.h

@@ -12,8 +12,6 @@ typedef struct {
     bool right_button;
 } mouse_data_t;
 
-extern mouse_data_t mouse_data;
-
 // Function declarations for USB 1.x HID mouse support
 bool usb_mouse_init(void);
 bool usb_mouse_detected(void);

kernel/pci.c

@@ -1,109 +0,0 @@
-#include "pci.h"
-#include "io.h"
-
-/* --- Configuration Access Functions --- */
-
-uint32_t pci_config_read_dword(uint8_t bus, uint8_t slot, uint8_t func, uint8_t offset) {
-    uint32_t address = (uint32_t)((uint32_t)1 << 31) | 
-                       ((uint32_t)bus << 16) | 
-                       ((uint32_t)slot << 11) | 
-                       ((uint32_t)func << 8) | 
-                       (offset & 0xFC);
-    outl(PCI_CONFIG_ADDRESS, address);
-    return inl(PCI_CONFIG_DATA);
-}
-
-void pci_config_write_dword(uint8_t bus, uint8_t slot, uint8_t func, uint8_t offset, uint32_t data) {
-    uint32_t address = (uint32_t)((uint32_t)1 << 31) | 
-                       ((uint32_t)bus << 16) | 
-                       ((uint32_t)slot << 11) | 
-                       ((uint32_t)func << 8) | 
-                       (offset & 0xFC);
-    outl(PCI_CONFIG_ADDRESS, address);
-    outl(PCI_CONFIG_DATA, data);
-}
-
-/* To read a word or byte, we read the Dword and shift/mask */
-uint16_t pci_config_read_word(uint8_t bus, uint8_t slot, uint8_t func, uint8_t offset) {
-    uint32_t dword = pci_config_read_dword(bus, slot, func, offset);
-    return (uint16_t)((dword >> ((offset & 2) * 8)) & 0xFFFF);
-}
-
-uint8_t pci_config_read_byte(uint8_t bus, uint8_t slot, uint8_t func, uint8_t offset) {
-    uint32_t dword = pci_config_read_dword(bus, slot, func, offset);
-    return (uint8_t)((dword >> ((offset & 3) * 8)) & 0xFF);
-}
-
-/* --- BAR Decoding Logic --- */
-
-pci_bar_t pci_get_bar(uint8_t bus, uint8_t slot, uint8_t func, uint8_t bar_index) {
-    pci_bar_t bar = {0};
-    uint8_t offset = PCI_REG_BAR0 + (bar_index * 4);
-    
-    uint32_t initial_val = pci_config_read_dword(bus, slot, func, offset);
-    
-    // The Size Masking Trick
-    pci_config_write_dword(bus, slot, func, offset, 0xFFFFFFFF);
-    uint32_t mask = pci_config_read_dword(bus, slot, func, offset);
-    pci_config_write_dword(bus, slot, func, offset, initial_val); // Restore
-    
-    if (initial_val & 0x1) {
-        // I/O Space BAR
-        bar.is_io = true;
-        bar.base_address = initial_val & 0xFFFFFFFC;
-        bar.size = ~(mask & 0xFFFFFFFC) + 1;
-    } else {
-        // Memory Space BAR
-        bar.is_io = false;
-        bar.base_address = initial_val & 0xFFFFFFF0;
-        bar.is_prefetchable = (initial_val & 0x8) != 0;
-        bar.size = ~(mask & 0xFFFFFFF0) + 1;
-    }
-    
-    return bar;
-}
-
-/* --- Enumeration and Discovery --- */
-
-void pci_check_function(uint8_t bus, uint8_t slot, uint8_t func) {
-    uint16_t vendor_id = pci_config_read_word(bus, slot, func, PCI_REG_VENDOR_ID);
-    if (vendor_id == 0xFFFF) return; 
-
-    uint16_t device_id = pci_config_read_word(bus, slot, func, PCI_REG_DEVICE_ID);
-    uint8_t class_code = pci_config_read_byte(bus, slot, func, PCI_REG_CLASS);
-    
-    /* Optional: Set Master Latency Timer if it is 0. 
-       A value of 32 (0x20) or 64 (0x40) is typical. 
-    */
-    uint8_t latency = pci_config_read_byte(bus, slot, func, PCI_REG_LATENCY_TIMER);
-    if (latency == 0) {
-        // pci_config_write_byte would be needed here, or write a dword with the byte modified
-        uint32_t reg_0c = pci_config_read_dword(bus, slot, func, 0x0C);
-        reg_0c |= (0x20 << 8); // Set latency to 32
-        pci_config_write_dword(bus, slot, func, 0x0C, reg_0c);
-    }
-
-    // Replace with your kernel's print/logging function
-    // printf("Found PCI Device: %x:%x Class: %x at %d:%d:%d\n", vendor_id, device_id, class_code, bus, slot, func);
-}
-
-void pci_init(void) {
-    for (uint16_t bus = 0; bus < 256; bus++) {
-        for (uint8_t slot = 0; slot < 32; slot++) {
-            // Check Function 0 first
-            uint16_t vendor = pci_config_read_word(bus, slot, 0, PCI_REG_VENDOR_ID);
-            if (vendor == 0xFFFF) continue;
-
-            pci_check_function(bus, slot, 0);
-
-            // Check if this is a multi-function device
-            uint8_t header_type = pci_config_read_byte(bus, slot, 0, PCI_REG_HEADER_TYPE);
-            if (header_type & 0x80) {
-                // Check functions 1-7
-                for (uint8_t func = 1; func < 8; func++) {
-                    pci_check_function(bus, slot, func);
-                }
-            }
-        }
-    }
-}

kernel/pci.h

@@ -1,60 +0,0 @@
-#ifndef PCI_H
-#define PCI_H
-
-#include <stdint.h>
-#include <stdbool.h>
-
-/* I/O Ports for PCI Configuration Mechanism #1 */
-#define PCI_CONFIG_ADDRESS 0xCF8
-#define PCI_CONFIG_DATA    0xCFC
-
-/* Common PCI Configuration Register Offsets */
-#define PCI_REG_VENDOR_ID       0x00
-#define PCI_REG_DEVICE_ID       0x02
-#define PCI_REG_COMMAND         0x04
-#define PCI_REG_STATUS          0x06
-#define PCI_REG_REVISION_ID     0x08
-#define PCI_REG_PROG_IF         0x09
-#define PCI_REG_SUBCLASS        0x0A
-#define PCI_REG_CLASS           0x0B
-#define PCI_REG_CACHE_LINE_SIZE 0x0C
-#define PCI_REG_LATENCY_TIMER   0x0D
-#define PCI_REG_HEADER_TYPE     0x0E
-#define PCI_REG_BIST            0x0F
-#define PCI_REG_BAR0            0x10
-#define PCI_REG_BAR1            0x14
-#define PCI_REG_BAR2            0x18
-#define PCI_REG_BAR3            0x1C
-#define PCI_REG_BAR4            0x20
-#define PCI_REG_BAR5            0x24
-#define PCI_REG_INTERRUPT_LINE  0x3C
-
-typedef struct {
-    uint32_t base_address;
-    uint32_t size;
-    bool     is_io;
-    bool     is_prefetchable; // Only for Memory BARs
-} pci_bar_t;
-
-typedef struct {
-    uint8_t  bus;
-    uint8_t  device;
-    uint8_t  function;
-    uint16_t vendor_id;
-    uint16_t device_id;
-    uint8_t  class_code;
-    uint8_t  subclass;
-    uint8_t  interrupt_line;
-} pci_dev_t;
-
-/* Function Prototypes */
-uint32_t pci_config_read_dword(uint8_t bus, uint8_t slot, uint8_t func, uint8_t offset);
-void     pci_config_write_dword(uint8_t bus, uint8_t slot, uint8_t func, uint8_t offset, uint32_t data);
-
-uint16_t pci_config_read_word(uint8_t bus, uint8_t slot, uint8_t func, uint8_t offset);
-uint8_t  pci_config_read_byte(uint8_t bus, uint8_t slot, uint8_t func, uint8_t offset);
-
-pci_bar_t pci_get_bar(uint8_t bus, uint8_t slot, uint8_t func, uint8_t bar_index);
-void      pci_init(void);
-
-#endif

kernel/ps2.c

@@ -1,107 +0,0 @@
-#include "ps2.h"
-#include "io.h"
-
-/* --- Controller Synchronization --- */
-
-// Wait until the controller is ready to receive a byte
-static void ps2_wait_write() {
-    while (inb(PS2_STATUS_REG) & PS2_STATUS_INPUT);
-}
-
-// Wait until the controller has a byte for us to read
-static void ps2_wait_read() {
-    while (!(inb(PS2_STATUS_REG) & PS2_STATUS_OUTPUT));
-}
-
-/* --- Initialization --- */
-
-void ps2_write_device(uint8_t command) {
-    ps2_wait_write();
-    outb(PS2_DATA_PORT, command);
-}
-
-void ps2_write_mouse(uint8_t data) {
-    ps2_wait_write();
-    outb(PS2_COMMAND_REG, PS2_CMD_WRITE_MOUSE); // "Next byte goes to mouse"
-    ps2_wait_write();
-    outb(PS2_DATA_PORT, data);
-}
-
-void ps2_init(void) {
-    // 1. Disable Devices
-    ps2_wait_write();
-    outb(PS2_COMMAND_REG, PS2_CMD_DISABLE_KB);
-    ps2_wait_write();
-    outb(PS2_COMMAND_REG, PS2_CMD_DISABLE_MS);
-
-    // 2. Flush Output Buffer
-    while (inb(PS2_STATUS_REG) & PS2_STATUS_OUTPUT) {
-        inb(PS2_DATA_PORT);
-    }
-
-    // 3. Set Controller Configuration Byte
-    // Bit 0: KB Interrupt, Bit 1: Mouse Interrupt, Bit 6: Translation
-    ps2_wait_write();
-    outb(PS2_COMMAND_REG, PS2_CMD_READ_CONFIG);
-    ps2_wait_read();
-    uint8_t status = inb(PS2_DATA_PORT);
-    status |= (1 << 0) | (1 << 1); // Enable IRQ 1 and IRQ 12
-    
-    ps2_wait_write();
-    outb(PS2_COMMAND_REG, PS2_CMD_WRITE_CONFIG);
-    ps2_wait_write();
-    outb(PS2_DATA_PORT, status);
-
-    // 4. Enable Devices
-    ps2_wait_write();
-    outb(PS2_COMMAND_REG, PS2_CMD_ENABLE_KB);
-    ps2_wait_write();
-    outb(PS2_COMMAND_REG, PS2_CMD_ENABLE_MS);
-
-    // 5. Initialize Mouse (The mouse won't send IRQs until you tell it to)
-    ps2_write_mouse(MOUSE_CMD_SET_DEFAULTS);
-    ps2_wait_read(); inb(PS2_DATA_PORT); // Read ACK (0xFA)
-    
-    ps2_write_mouse(MOUSE_CMD_ENABLE_SCAN);
-    ps2_wait_read(); inb(PS2_DATA_PORT); // Read ACK (0xFA)
-}
-
-/* --- IRQ Handlers --- */
-
-// Called from IRQ 1 (Keyboard)
-void ps2_keyboard_handler(void) {
-    uint8_t scancode = inb(PS2_DATA_PORT);
-    // Process scancode (e.g., put it into a circular buffer)
-}
-
-// Called from IRQ 12 (Mouse)
-static uint8_t mouse_cycle = 0;
-static uint8_t mouse_bytes[3];
-
-void ps2_mouse_handler(void) {
-    uint8_t status = inb(PS2_STATUS_REG);
-    
-    // Ensure this is actually mouse data
-    if (!(status & PS2_STATUS_MOUSE)) return;
-
-    mouse_bytes[mouse_cycle++] = inb(PS2_DATA_PORT);
-
-    if (mouse_cycle == 3) {
-        mouse_cycle = 0;
-        
-        // Byte 0: Flags (Buttons, Signs)
-        // Byte 1: X Delta
-        // Byte 2: Y Delta
-        
-        mouse_state_t state;
-        state.left_button   = (mouse_bytes[0] & 0x01);
-        state.right_button  = (mouse_bytes[0] & 0x02);
-        state.middle_button = (mouse_bytes[0] & 0x04);
-
-        // Handle negative deltas (signed 9-bit logic)
-        state.x_delta = (int8_t)mouse_bytes[1];
-        state.y_delta = (int8_t)mouse_bytes[2];
-
-        // Update your kernel's internal mouse position here
-    }
-}

kernel/ps2.h

@@ -1,45 +0,0 @@
-#ifndef PS2_H
-#define PS2_H
-
-#include <stdint.h>
-#include <stdbool.h>
-
-/* I/O Ports */
-#define PS2_DATA_PORT       0x60
-#define PS2_STATUS_REG      0x64
-#define PS2_COMMAND_REG     0x64
-
-/* Status Register Bits */
-#define PS2_STATUS_OUTPUT   0x01 // 1 = Data ready to be read
-#define PS2_STATUS_INPUT    0x02 // 1 = Controller busy, don't write yet
-#define PS2_STATUS_SYS      0x04 // System flag
-#define PS2_STATUS_CMD_DATA 0x08 // 0 = Data written to 0x60, 1 = Cmd to 0x64
-#define PS2_STATUS_MOUSE    0x20 // 1 = Mouse data, 0 = Keyboard data
-
-/* Controller Commands */
-#define PS2_CMD_READ_CONFIG  0x20
-#define PS2_CMD_WRITE_CONFIG 0x60
-#define PS2_CMD_DISABLE_MS   0xA7
-#define PS2_CMD_ENABLE_MS    0xA8
-#define PS2_CMD_DISABLE_KB   0xAD
-#define PS2_CMD_ENABLE_KB    0xAE
-#define PS2_CMD_WRITE_MOUSE  0xD4
-
-/* Mouse Commands */
-#define MOUSE_CMD_SET_DEFAULTS 0xF6
-#define MOUSE_CMD_ENABLE_SCAN  0xF4
-
-typedef struct {
-    int8_t  x_delta;
-    int8_t  y_delta;
-    bool    left_button;
-    bool    right_button;
-    bool    middle_button;
-} mouse_state_t;
-
-/* Public API */
-void ps2_init(void);
-void ps2_keyboard_handler(void);
-void ps2_mouse_handler(void);
-
-#endif

kernel/threading.c

@@ -4,8 +4,8 @@
 #include "print.h"
 #include "threading.h"
 
-#define MAX_THREADS 16          // Maximum number of threads
+#define MAX_THREADS 16           // Maximum number of threads
-#define THREAD_STACK_SIZE 8192  // Stack size for each thread
+#define THREAD_STACK_SIZE 8192   // Stack size for each thread
 
 // The thread table stores information about all threads
 static Thread thread_table[MAX_THREADS];
@@ -16,106 +16,103 @@ static uint32_t num_threads = 0;     // Number of active threads
 static volatile int mutex_locked = 0;
 
 // Function declaration for context_switch
-void context_switch(Thread* next);
+void context_switch(Thread *next);
 
 // Initialize the threading system
 void thread_init(void) {
-  memset(thread_table, 0, sizeof(thread_table));
+    memset(thread_table, 0, sizeof(thread_table));
-  num_threads = 0;
+    num_threads = 0;
 }
 
 // Create a new thread
-void thread_create(Thread* thread __attribute__((unused)),
+void thread_create(Thread *thread __attribute__((unused)), void (*start_routine)(void *), void *arg) {
-                   void (*start_routine)(void*), void* arg) {
+    if (num_threads >= MAX_THREADS) {
-  if (num_threads >= MAX_THREADS) {
+        my_printf("Error: Maximum thread count reached.\n");
-    my_printf("Error: Maximum thread count reached.\n");
+        return;
-    return;
+    }
-  }
 
-  // Find an empty slot for the new thread
+    // Find an empty slot for the new thread
-  int index = num_threads++;
+    int index = num_threads++;
-  thread_table[index] = (Thread){0};
+    thread_table[index] = (Thread){0};
+    
+    // Set up the new thread
+    thread_table[index].start_routine = start_routine;
+    thread_table[index].arg = arg;
+    thread_table[index].stack_size = THREAD_STACK_SIZE;
+    thread_table[index].stack = (uint32_t*)malloc(THREAD_STACK_SIZE);
+    thread_table[index].stack_top = thread_table[index].stack + THREAD_STACK_SIZE / sizeof(uint32_t);
 
-  // Set up the new thread
+    // Initialize the stack (simulate pushing the function's return address)
-  thread_table[index].start_routine = start_routine;
+    uint32_t *stack_top = thread_table[index].stack_top;
-  thread_table[index].arg = arg;
+    *(--stack_top) = (uint32_t)start_routine;  // Return address (the thread's entry point)
-  thread_table[index].stack_size = THREAD_STACK_SIZE;
+    *(--stack_top) = (uint32_t)arg;            // Argument to pass to the thread
-  thread_table[index].stack = (uint32_t*)malloc(THREAD_STACK_SIZE);
-  thread_table[index].stack_top =
-      thread_table[index].stack + THREAD_STACK_SIZE / sizeof(uint32_t);
 
-  // Initialize the stack (simulate pushing the function's return address)
+    // Set the thread's state to ready
-  uint32_t* stack_top = thread_table[index].stack_top;
+    thread_table[index].state = THREAD_READY;
-  *(--stack_top) =
-      (uint32_t)start_routine;     // Return address (the thread's entry point)
-  *(--stack_top) = (uint32_t)arg;  // Argument to pass to the thread
 
-  // Set the thread's state to ready
+    // If this is the first thread, switch to it
-  thread_table[index].state = THREAD_READY;
+    if (index == 0) {
-
+        scheduler();
-  // If this is the first thread, switch to it
+    }
-  if (index == 0) {
-    scheduler();
-  }
 }
 
 // Yield the CPU to another thread
 void thread_yield(void) {
-  // Find the next thread in a round-robin manner
+    // Find the next thread in a round-robin manner
-  uint32_t next_thread = (current_thread + 1) % num_threads;
+    uint32_t next_thread = (current_thread + 1) % num_threads;
-  while (next_thread != current_thread &&
+    while (next_thread != current_thread && thread_table[next_thread].state != THREAD_READY) {
-         thread_table[next_thread].state != THREAD_READY) {
+        next_thread = (next_thread + 1) % num_threads;
-    next_thread = (next_thread + 1) % num_threads;
+    }
-  }
 
-  if (next_thread != current_thread) {
+    if (next_thread != current_thread) {
-    current_thread = next_thread;
+        current_thread = next_thread;
-    scheduler();
+        scheduler();
-  }
+    }
 }
 
 // Exit the current thread
 void thread_exit(void) {
-  thread_table[current_thread].state =
+    thread_table[current_thread].state = THREAD_BLOCKED;  // Mark the thread as blocked (finished)
-      THREAD_BLOCKED;  // Mark the thread as blocked (finished)
+    free(thread_table[current_thread].stack);             // Free the thread's stack
-  free(thread_table[current_thread].stack);  // Free the thread's stack
+    num_threads--;                                       // Decrease thread count
-  num_threads--;                             // Decrease thread count
 
-  // Yield to the next thread
+    // Yield to the next thread
-  thread_yield();
+    thread_yield();
 }
 
 // Scheduler: This function selects the next thread to run
 void scheduler(void) {
-  // Find the next ready thread
+    // Find the next ready thread
-  uint32_t next_thread = (current_thread + 1) % num_threads;
+    uint32_t next_thread = (current_thread + 1) % num_threads;
-  while (thread_table[next_thread].state != THREAD_READY) {
+    while (thread_table[next_thread].state != THREAD_READY) {
-    next_thread = (next_thread + 1) % num_threads;
+        next_thread = (next_thread + 1) % num_threads;
-  }
+    }
 
-  if (next_thread != current_thread) {
+    if (next_thread != current_thread) {
-    current_thread = next_thread;
+        current_thread = next_thread;
-    context_switch(&thread_table[current_thread]);
+        context_switch(&thread_table[current_thread]);
-  }
+    }
 }
 
-// Context switch to the next thread (assembly would go here to save/load
+// Context switch to the next thread (assembly would go here to save/load registers)
-// registers)
+void context_switch(Thread *next) {
-void context_switch(Thread* next) {
+    // For simplicity, context switching in this example would involve saving/restoring registers.
-  // For simplicity, context switching in this example would involve
+    // In a real system, you would need to save the CPU state (registers) and restore the next thread's state.
-  // saving/restoring registers. In a real system, you would need to save the
+    my_printf("Switching to thread...\n");
-  // CPU state (registers) and restore the next thread's state.
+    next->start_routine(next->arg);  // Start running the next thread
-  my_printf("Switching to thread...\n");
-  next->start_routine(next->arg);  // Start running the next thread
 }
 
 // Simple mutex functions (spinlock)
-void mutex_init(void) { mutex_locked = 0; }
+void mutex_init(void) {
-
+    mutex_locked = 0;
-void mutex_lock(void) {
-  while (__sync_lock_test_and_set(&mutex_locked, 1)) {
-    // Busy wait (spinlock)
-  }
 }
 
-void mutex_unlock(void) { __sync_lock_release(&mutex_locked); }
+void mutex_lock(void) {
+    while (__sync_lock_test_and_set(&mutex_locked, 1)) {
+        // Busy wait (spinlock)
+    }
+}
+
+void mutex_unlock(void) {
+    __sync_lock_release(&mutex_locked);
+}

kernel/vga.c

@@ -1,9 +1,9 @@
+#include "vga.h"
 #include <stddef.h>
 #include <stdbool.h>
 #include <string.h>
 #include <stdarg.h>
 #include "string_utils.h"
-#include "vga.h"
 
 void outb(uint16_t port, uint8_t value) {
     __asm__ volatile("outb %0, %1" : : "a"(value), "Nd"(port));
@@ -134,7 +134,7 @@ void vga_printf(const char* format, ...) {
     va_end(args);
     
     // Now you can use the buffer with vga_write_string
-    vga_write_string(buffer, strlen(buffer)); // Use my_strlen instead of strlen
+    vga_write_string(buffer, my_strlen(buffer)); // Use my_strlen instead of strlen
 }
 
 void vga_init(void) {

kernel/vga.h

@@ -35,7 +35,6 @@ typedef enum {
 // Function prototypes
 uint8_t vga_entry_color(vga_color fg, vga_color bg);
 uint16_t vga_entry(unsigned char uc, uint8_t color);
-void vga_init(void);
 
 void vga_put_entry_at(char c, uint8_t color, size_t x, size_t y);
 void vga_clear(uint8_t color);
@@ -51,4 +50,4 @@ void vga_set_cursor_blink_rate(uint8_t rate);
 
 void vga_printf(const char* format, ...);
 
-#endif
+#endif